(Animation Nodes) How can I make objects rotate to face the direction of the normals of a mesh?
Use an Object Mesh Data node to get the face data of the target object. Connect the Polygons output to an Object Instancer and create a loop subprogram that has a polygon and an object iterator. With the Mesh data node selected you can press W and choose polygons to create the loop and add another object list iterator to it.

For the subprogram, connect the object to an Object Transform Output and use a Polygon Info node to get the location and normal of each face. Connecting the polygon normal to the object rotation input will create a Direction to Rotation node that gives the direction you want. The center output will give you the location to place each instance.